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>> 26 // $Id: G4KleinNishinaCompton.cc 74309 2013-10-03 06:42:30Z gcosmo $
26 // 27 //
27 // ------------------------------------------- 28 // -------------------------------------------------------------------
28 // 29 //
29 // GEANT4 Class file 30 // GEANT4 Class file
30 // 31 //
31 // 32 //
32 // File name: G4KleinNishinaCompton 33 // File name: G4KleinNishinaCompton
33 // 34 //
34 // Author: Vladimir Ivanchenko on base 35 // Author: Vladimir Ivanchenko on base of Michel Maire code
35 // 36 //
36 // Creation date: 15.03.2005 37 // Creation date: 15.03.2005
37 // 38 //
38 // Modifications: 39 // Modifications:
39 // 18-04-05 Use G4ParticleChangeForGamma (V.Iv 40 // 18-04-05 Use G4ParticleChangeForGamma (V.Ivantchenko)
40 // 27-03-06 Remove upper limit of cross sectio 41 // 27-03-06 Remove upper limit of cross section (V.Ivantchenko)
41 // 42 //
42 // Class Description: 43 // Class Description:
43 // 44 //
44 // ------------------------------------------- 45 // -------------------------------------------------------------------
45 // 46 //
46 //....oooOO0OOooo........oooOO0OOooo........oo 47 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
47 //....oooOO0OOooo........oooOO0OOooo........oo 48 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
48 49
49 #include "G4KleinNishinaCompton.hh" 50 #include "G4KleinNishinaCompton.hh"
50 #include "G4PhysicalConstants.hh" 51 #include "G4PhysicalConstants.hh"
51 #include "G4SystemOfUnits.hh" 52 #include "G4SystemOfUnits.hh"
52 #include "G4Electron.hh" 53 #include "G4Electron.hh"
53 #include "G4Gamma.hh" 54 #include "G4Gamma.hh"
54 #include "Randomize.hh" 55 #include "Randomize.hh"
55 #include "G4DataVector.hh" 56 #include "G4DataVector.hh"
56 #include "G4ParticleChangeForGamma.hh" 57 #include "G4ParticleChangeForGamma.hh"
57 #include "G4Log.hh" 58 #include "G4Log.hh"
58 #include "G4Exp.hh" 59 #include "G4Exp.hh"
59 60
60 //....oooOO0OOooo........oooOO0OOooo........oo 61 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
61 62
62 using namespace std; 63 using namespace std;
63 64
>> 65 static const G4double
>> 66 d1= 2.7965e-1*barn, d2=-1.8300e-1*barn, d3= 6.7527 *barn, d4=-1.9798e+1*barn,
>> 67 e1= 1.9756e-5*barn, e2=-1.0205e-2*barn, e3=-7.3913e-2*barn, e4= 2.7079e-2*barn,
>> 68 f1=-3.9178e-7*barn, f2= 6.8241e-5*barn, f3= 6.0480e-5*barn, f4= 3.0274e-4*barn;
>> 69
64 G4KleinNishinaCompton::G4KleinNishinaCompton(c 70 G4KleinNishinaCompton::G4KleinNishinaCompton(const G4ParticleDefinition*,
65 c 71 const G4String& nam)
66 : G4VEmModel(nam) 72 : G4VEmModel(nam)
67 { 73 {
68 theGamma = G4Gamma::Gamma(); 74 theGamma = G4Gamma::Gamma();
69 theElectron = G4Electron::Electron(); 75 theElectron = G4Electron::Electron();
70 lowestSecondaryEnergy = 100.0*eV; << 76 lowestGammaEnergy = 1.0*eV;
71 fParticleChange = nullptr; << 77 fParticleChange = 0;
72 } 78 }
73 79
74 //....oooOO0OOooo........oooOO0OOooo........oo 80 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
75 81
76 G4KleinNishinaCompton::~G4KleinNishinaCompton( << 82 G4KleinNishinaCompton::~G4KleinNishinaCompton()
>> 83 {}
77 84
78 //....oooOO0OOooo........oooOO0OOooo........oo 85 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
79 86
80 void G4KleinNishinaCompton::Initialise(const G 87 void G4KleinNishinaCompton::Initialise(const G4ParticleDefinition* p,
81 const G 88 const G4DataVector& cuts)
82 { 89 {
83 if(IsMaster()) { InitialiseElementSelectors( 90 if(IsMaster()) { InitialiseElementSelectors(p, cuts); }
84 if(nullptr == fParticleChange) { << 91 if(!fParticleChange) { fParticleChange = GetParticleChangeForGamma(); }
85 fParticleChange = GetParticleChangeForGamm <<
86 } <<
87 } 92 }
88 93
89 //....oooOO0OOooo........oooOO0OOooo........oo 94 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
90 95
91 void G4KleinNishinaCompton::InitialiseLocal(co 96 void G4KleinNishinaCompton::InitialiseLocal(const G4ParticleDefinition*,
92 G4 << 97 G4VEmModel* masterModel)
93 { 98 {
94 SetElementSelectors(masterModel->GetElementS 99 SetElementSelectors(masterModel->GetElementSelectors());
95 } 100 }
96 101
97 //....oooOO0OOooo........oooOO0OOooo........oo 102 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
98 103
99 G4double G4KleinNishinaCompton::ComputeCrossSe 104 G4double G4KleinNishinaCompton::ComputeCrossSectionPerAtom(
100 const G 105 const G4ParticleDefinition*,
101 G 106 G4double GammaEnergy,
102 G 107 G4double Z, G4double,
103 G 108 G4double, G4double)
104 { 109 {
105 G4double xSection = 0.0 ; 110 G4double xSection = 0.0 ;
106 if (GammaEnergy <= LowEnergyLimit()) { retur << 111 if ( Z < 0.9999 ) return xSection;
>> 112 if ( GammaEnergy < 0.1*keV ) return xSection;
>> 113 // if ( GammaEnergy > (100.*GeV/Z) ) return xSection;
107 114
108 static const G4double a = 20.0 , b = 230.0 , 115 static const G4double a = 20.0 , b = 230.0 , c = 440.0;
109 <<
110 static const G4double <<
111 d1= 2.7965e-1*CLHEP::barn, d2=-1.8300e-1*CLH <<
112 d3= 6.7527 *CLHEP::barn, d4=-1.9798e+1*CLH <<
113 e1= 1.9756e-5*CLHEP::barn, e2=-1.0205e-2*CLH <<
114 e3=-7.3913e-2*CLHEP::barn, e4= 2.7079e-2*CLH <<
115 f1=-3.9178e-7*CLHEP::barn, f2= 6.8241e-5*CLH <<
116 f3= 6.0480e-5*CLHEP::barn, f4= 3.0274e-4*CLH <<
117 116
118 G4double p1Z = Z*(d1 + e1*Z + f1*Z*Z), p2Z = 117 G4double p1Z = Z*(d1 + e1*Z + f1*Z*Z), p2Z = Z*(d2 + e2*Z + f2*Z*Z),
119 p3Z = Z*(d3 + e3*Z + f3*Z*Z), p4Z = 118 p3Z = Z*(d3 + e3*Z + f3*Z*Z), p4Z = Z*(d4 + e4*Z + f4*Z*Z);
120 119
121 G4double T0 = 15.0*keV; 120 G4double T0 = 15.0*keV;
122 if (Z < 1.5) { T0 = 40.0*keV; } << 121 if (Z < 1.5) T0 = 40.0*keV;
123 122
124 G4double X = max(GammaEnergy, T0) / electr 123 G4double X = max(GammaEnergy, T0) / electron_mass_c2;
125 xSection = p1Z*G4Log(1.+2.*X)/X 124 xSection = p1Z*G4Log(1.+2.*X)/X
126 + (p2Z + p3Z*X + p4Z*X*X)/(1. + 125 + (p2Z + p3Z*X + p4Z*X*X)/(1. + a*X + b*X*X + c*X*X*X);
127 << 126
128 // modification for low energy. (special ca 127 // modification for low energy. (special case for Hydrogen)
129 if (GammaEnergy < T0) { 128 if (GammaEnergy < T0) {
130 static const G4double dT0 = keV; << 129 G4double dT0 = 1.*keV;
131 X = (T0+dT0) / electron_mass_c2 ; 130 X = (T0+dT0) / electron_mass_c2 ;
132 G4double sigma = p1Z*G4Log(1.+2*X)/X 131 G4double sigma = p1Z*G4Log(1.+2*X)/X
133 + (p2Z + p3Z*X + p4Z*X*X)/ 132 + (p2Z + p3Z*X + p4Z*X*X)/(1. + a*X + b*X*X + c*X*X*X);
134 G4double c1 = -T0*(sigma-xSection)/(xSec 133 G4double c1 = -T0*(sigma-xSection)/(xSection*dT0);
135 G4double c2 = 0.150; 134 G4double c2 = 0.150;
136 if (Z > 1.5) { c2 = 0.375-0.0556*G4Log(Z); << 135 if (Z > 1.5) c2 = 0.375-0.0556*G4Log(Z);
137 G4double y = G4Log(GammaEnergy/T0); 136 G4double y = G4Log(GammaEnergy/T0);
138 xSection *= G4Exp(-y*(c1+c2*y)); 137 xSection *= G4Exp(-y*(c1+c2*y));
139 } 138 }
140 // G4cout<<"e= "<< GammaEnergy<<" Z= "<<Z<<" << 139 // G4cout << "e= " << GammaEnergy << " Z= " << Z << " cross= " << xSection << G4endl;
141 return xSection; 140 return xSection;
142 } 141 }
143 142
144 //....oooOO0OOooo........oooOO0OOooo........oo 143 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
145 144
146 void G4KleinNishinaCompton::SampleSecondaries( << 145 void G4KleinNishinaCompton::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect,
147 std::vector<G4Dyna << 146 const G4MaterialCutsCouple*,
148 const G4MaterialCu << 147 const G4DynamicParticle* aDynamicGamma,
149 const G4DynamicPar << 148 G4double,
150 G4double, << 149 G4double)
151 G4double) <<
152 { 150 {
153 // The scattered gamma energy is sampled acc 151 // The scattered gamma energy is sampled according to Klein - Nishina formula.
154 // The random number techniques of Butcher & 152 // The random number techniques of Butcher & Messel are used
155 // (Nuc Phys 20(1960),15). 153 // (Nuc Phys 20(1960),15).
156 // Note : Effects due to binding of atomic e 154 // Note : Effects due to binding of atomic electrons are negliged.
157 155
158 G4double gamEnergy0 = aDynamicGamma->GetKine 156 G4double gamEnergy0 = aDynamicGamma->GetKineticEnergy();
159 157
160 // do nothing below the threshold << 158 // extra protection
161 if(gamEnergy0 <= LowEnergyLimit()) { return; << 159 if(gamEnergy0 < lowestGammaEnergy) {
>> 160 fParticleChange->ProposeTrackStatus(fStopAndKill);
>> 161 fParticleChange->ProposeLocalEnergyDeposit(gamEnergy0);
>> 162 fParticleChange->SetProposedKineticEnergy(0.0);
>> 163 return;
>> 164 }
162 165
163 G4double E0_m = gamEnergy0 / electron_mass_c 166 G4double E0_m = gamEnergy0 / electron_mass_c2 ;
164 167
165 G4ThreeVector gamDirection0 = aDynamicGamma- 168 G4ThreeVector gamDirection0 = aDynamicGamma->GetMomentumDirection();
166 169
167 // 170 //
168 // sample the energy rate of the scattered g 171 // sample the energy rate of the scattered gamma
169 // 172 //
170 173
171 G4double epsilon, epsilonsq, onecost, sint2, 174 G4double epsilon, epsilonsq, onecost, sint2, greject ;
172 175
173 G4double eps0 = 1./(1. + 2.*E0_m); 176 G4double eps0 = 1./(1. + 2.*E0_m);
174 G4double epsilon0sq = eps0*eps0; 177 G4double epsilon0sq = eps0*eps0;
175 G4double alpha1 = - G4Log(eps0); 178 G4double alpha1 = - G4Log(eps0);
176 G4double alpha2 = alpha1 + 0.5*(1.- epsi << 179 G4double alpha2 = 0.5*(1.- epsilon0sq);
177 <<
178 CLHEP::HepRandomEngine* rndmEngineMod = G4Ra <<
179 G4double rndm[3]; <<
180 180
181 static const G4int nlooplim = 1000; <<
182 G4int nloop = 0; <<
183 do { 181 do {
184 ++nloop; << 182 if ( alpha1/(alpha1+alpha2) > G4UniformRand() ) {
185 // false interaction if too many iteration << 183 epsilon = G4Exp(-alpha1*G4UniformRand()); // eps0**r
186 if(nloop > nlooplim) { return; } <<
187 <<
188 // 3 random numbers to sample scattering <<
189 rndmEngineMod->flatArray(3, rndm); <<
190 <<
191 if ( alpha1 > alpha2*rndm[0] ) { <<
192 epsilon = G4Exp(-alpha1*rndm[1]); // <<
193 epsilonsq = epsilon*epsilon; 184 epsilonsq = epsilon*epsilon;
194 185
195 } else { 186 } else {
196 epsilonsq = epsilon0sq + (1.- epsilon0sq << 187 epsilonsq = epsilon0sq + (1.- epsilon0sq)*G4UniformRand();
197 epsilon = sqrt(epsilonsq); 188 epsilon = sqrt(epsilonsq);
198 }; 189 };
199 190
200 onecost = (1.- epsilon)/(epsilon*E0_m); 191 onecost = (1.- epsilon)/(epsilon*E0_m);
201 sint2 = onecost*(2.-onecost); 192 sint2 = onecost*(2.-onecost);
202 greject = 1. - epsilon*sint2/(1.+ epsilons 193 greject = 1. - epsilon*sint2/(1.+ epsilonsq);
203 194
204 // Loop checking, 03-Aug-2015, Vladimir Iv << 195 } while (greject < G4UniformRand());
205 } while (greject < rndm[2]); <<
206 196
207 // 197 //
208 // scattered gamma angles. ( Z - axis along 198 // scattered gamma angles. ( Z - axis along the parent gamma)
209 // 199 //
210 200
211 if(sint2 < 0.0) { sint2 = 0.0; } 201 if(sint2 < 0.0) { sint2 = 0.0; }
212 G4double cosTeta = 1. - onecost; 202 G4double cosTeta = 1. - onecost;
213 G4double sinTeta = sqrt (sint2); 203 G4double sinTeta = sqrt (sint2);
214 G4double Phi = twopi * rndmEngineMod->fl << 204 G4double Phi = twopi * G4UniformRand();
215 205
216 // 206 //
217 // update G4VParticleChange for the scattere 207 // update G4VParticleChange for the scattered gamma
218 // 208 //
219 209
220 G4ThreeVector gamDirection1(sinTeta*cos(Phi) 210 G4ThreeVector gamDirection1(sinTeta*cos(Phi), sinTeta*sin(Phi), cosTeta);
221 gamDirection1.rotateUz(gamDirection0); 211 gamDirection1.rotateUz(gamDirection0);
222 G4double gamEnergy1 = epsilon*gamEnergy0; 212 G4double gamEnergy1 = epsilon*gamEnergy0;
223 G4double edep = 0.0; << 213 if(gamEnergy1 > lowestGammaEnergy) {
224 if(gamEnergy1 > lowestSecondaryEnergy) { <<
225 fParticleChange->ProposeMomentumDirection( 214 fParticleChange->ProposeMomentumDirection(gamDirection1);
226 fParticleChange->SetProposedKineticEnergy( 215 fParticleChange->SetProposedKineticEnergy(gamEnergy1);
227 } else { 216 } else {
228 fParticleChange->ProposeTrackStatus(fStopA 217 fParticleChange->ProposeTrackStatus(fStopAndKill);
>> 218 fParticleChange->ProposeLocalEnergyDeposit(gamEnergy1);
229 fParticleChange->SetProposedKineticEnergy( 219 fParticleChange->SetProposedKineticEnergy(0.0);
230 edep = gamEnergy1; <<
231 } 220 }
232 221
233 // 222 //
234 // kinematic of the scattered electron 223 // kinematic of the scattered electron
235 // 224 //
236 225
237 G4double eKinEnergy = gamEnergy0 - gamEnergy 226 G4double eKinEnergy = gamEnergy0 - gamEnergy1;
238 227
239 if(eKinEnergy > lowestSecondaryEnergy) { << 228 if(eKinEnergy > DBL_MIN) {
240 G4ThreeVector eDirection = gamEnergy0*gamD 229 G4ThreeVector eDirection = gamEnergy0*gamDirection0 - gamEnergy1*gamDirection1;
241 eDirection = eDirection.unit(); 230 eDirection = eDirection.unit();
242 231
243 // create G4DynamicParticle object for the 232 // create G4DynamicParticle object for the electron.
244 auto dp = new G4DynamicParticle(theElectro << 233 G4DynamicParticle* dp = new G4DynamicParticle(theElectron,eDirection,eKinEnergy);
245 fvect->push_back(dp); 234 fvect->push_back(dp);
246 } else { <<
247 edep += eKinEnergy; <<
248 } <<
249 // energy balance <<
250 if(edep > 0.0) { <<
251 fParticleChange->ProposeLocalEnergyDeposit <<
252 } 235 }
253 } 236 }
254 237
255 //....oooOO0OOooo........oooOO0OOooo........oo 238 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
256 239
257 240
258 241